<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <div id="app">
      <h1 @click="type=!type" :class="type ? 'act-view' :'abt-view'">
        hello world{{type}}
      </h1>
    </div>
    <script src="../js/vue.js"></script>
    <script>
      new Vue({
        el: "#app",
        data: {
          type: false,
        },
      });
    </script>
  </body>
</html>
<style>
  .act-view {
    size: 35px;
    color: rgb(31, 212, 70);
  }
  .abt-view {
    size: 15px;
    color: rgb(212, 31, 31);
  }
</style>
